// and bucket and returns only policies that currently exist in MinIO. If
// bucketName is non-empty, additionally filters policies matching the bucket.
// The first returned value is the list of currently existing policies, and the
// second is their combined policy definition.
func (store *IAMStoreSys) FilterPolicies(policyName string, bucketName string) (string, policy.Policy) {
	cache := store.rlock()